Upload
walda
View
32
Download
0
Embed Size (px)
DESCRIPTION
Theory Summary & Prospects. John Ellis. Some 2014 Anniversaries. 150: Maxwell unified electromagnetic interactions 100: WW1 started 70 : D-Day 65 : Feyman diagrams, π 0 to γγ decay calculated by Steinberger 60 : Higgs got his PhD , CERN founded, Fermi extrapolation - PowerPoint PPT Presentation
Citation preview
John Ellis
Theory Summary & Prospects
Some 2014 Anniversaries• 150: Maxwell unified electromagnetic interactions• 100: WW1 started• 70: D-Day• 65: Feyman diagrams, π0 to γγ decay calculated by Steinberger• 60: Higgs got his PhD, CERN founded, Fermi extrapolation• 50: quarks, Ω-, CPV, charm, colour, EWSB, • 50: CMB, Bell’s theorem, Beatles invade US, civil rights• 40: J/ψ discovered• 35: Discovery of the gluon• 30: First LHC workshop, SUSY discovered at CERN p-pbar• 25: World-Wide Web, downfall of (much of) communism• 20: Approval of LHC• 0: Quantum gravitational radiation ?
The basis for everything at the LHC
Tests of SMTop physics
– Mass, AFB, …?
Producing new particles– e.g., Higgs
Possible signals– e.g., boosted jets
Backgrounds– e.g., pile-up
Hard QCD (1): Top• Basic parameter of SM; stability of EW vacuum?• Experimental world average:
mt = 173.34 ± 0.76 GeV• Monte Carlo mass!• MC mass pole mass?
± 0.7 GeV (MC running mass) + 0.5 GeV (running mass pole mass)• New measurements: CMS: 172.2±0.7 GeV, D0: 174.98±0.58±0.49 GeV
Moch
Boughezal, Ubiali, …
Hard QCD (2): Higgs• Many perturbative QCD calculations to NNLO• E.g., gg to H: agreement unsatisfactory
• Progress towards NNNLO calculationDittmaier, Neubert
Dittmaier
• EOS understood• Near-perfect fluid (string, holography, AdS/CFT)• Evidence for collective phenomena in p-Pb• Transverse shape of proton?• Energy ‘splashes’ to large angles in jet quenching• Screening (J/ψ, ϒ), regeneration (J/ψ)
Heavy-Ion CollisionsTeaney, Li, Kalweit, Scomparin, Cole
Excess in W+W- Production?
• CMS: 69.9 ± 2.8 ± 5.6 ± 3.1 pb @ 8 TeV:– Cf, TH: 57.3+2.3
-1.6 pb• ATLAS: 51.9 ± 2.0 ± 3.9 ± 2.0 pb @ 7 TeV:
– Cf, TH: 44.7+2.1-1.9 pb
• ‘Stop’ ambulance-chasing: scenarios with:–Light stop(s)–Wino–Bino
• Check consistency with direct searches
Curtin, Meade, Tien: arXiv:1406.0848;Kim, Rolbiecki, Sakurai, Tattersall: arXiv:1406.0858
Hallon
Flavour Physics• CKM picture works very well• Many successful predictions:
– Many modes of CPV– In K0, B0, B±, Bs systems– No sign of CPV in charm
• Also rare decays: Bs,d μ+μ-
• Could still be substantial BSM contribution
• Does new TeV physics copy CKM? Squarks non-degenerate?
Ligeti
Flavour Puzzles• CP asymmetries in D to Kπ?
• B0 to K*0 μ+ μ- angular distribution: P5’ anomaly
(3.7σ, 0.5% with LEE): explicable by Z’?•
• Vub: leakage to vector-like q?• Dimuon asymmetry at TeVatron? Ligeti
SM Measurements• Flavour, electroweak and Higgs measurements
complement searches for New Physics• From LEP paradox to LHC paradox
– Light Higgs + nothing else?– If something light, why no indirect evidence?
• If nothing light, is light Higgs unnatural?
Higgs Mass• Updates from ATLAS and CMS:
– CMS: 125.6 ± 0.4 ± 0.2 GeV from ZZ*– ATLAS:
• 2-σ!• Basic parameter of SM:
– Measure it!• Crucial for stability of
electroweak vacuum
Measuring ΓH @ LHC? • Constraint from off-shell H* ZZ: ΓH < 22 MeV
– But: Sensitive
to BSM e.g., dim-6
• Apparent mγγ ≠ mZZ* due to interference with QCDTough!
No BSM? Beware Historical Hubris
• "So many centuries after the Creation, it is unlikely that anyone could find hitherto unknown lands of any value” - Spanish Royal Commission, rejecting Christopher Columbus proposal to sail west, < 1492
• “The more important fundamental laws and facts of physical science have all been discovered” – Albert Michelson, 1894
• "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement" - Lord Kelvin, 1900
• “Is the End in Sight for Theoretical Physics?” – Stephen Hawking, 1980
Theoretical Confusion
• High mortality rate among theories• (MH, Mt) close to stability bound• Split SUSY? High-scale SUSY? • Modify/abandon naturalness? Does Nature care?• String landscape? • SUSY anywhere better than nowhere• SUSY could not explain the hierarchy• New ideas needed!
• « Empty » space is unstable• Dark matter• Origin of matter• Masses of neutrinos• Why is weak force so strong?• Inflation• Quantum gravity• …
The Standard Model Is Not Enough
Gianotti
Vacuum Instability in the Standard Model • Very sensitive to mt as well as MH
• Instability scale:
• mt = 173.8 ± 1 GeV log10(Λ/GeV) = 10.3 ± 1.3
Buttazzo, Degrassi, Giardino, Giudice, Sala, Salvio & Strumia, arXiv:1307.3536
LHCP
New CMS
New D0
Instability during Inflation?• Do quantum fluctuations drive us over the hill?
• Then Fokker-Planck evolution• Do AdS regions eat us?
– Disaster if so– If not, OK if more inflation
• Cure with non-ren’ble operator?
Hook, Kearns, Shakya & Zurek: arXiv:1404.5953
Kosowsky
Higgs as a Pseudo-Goldstone
Boson?
Loop cancellation mechanism
SupersymmetryLittle Higgs
‘Little Higgs’ models(breakdown of larger symmetry)
Global Analysis of Higgs-like Models• Rescale couplings: to bosons by a, to fermions by c
• Standard Model: a = c = 1JE & Tevong You, arXiv:1303.3879
b bbarτ τγ γW WZ ZGlobal
No evidence fordeviation from SM
Muehlleitner
It Walks and Quacks like a Higgs• Do couplings scale ~ mass? With scale = v?
• Red line = SM, dashed line = best fitJE & Tevong You, arXiv:1303.3879
Globalfit
BSM via Higher-Dimensional Operators• SM Higgs + corrections due to BSM
• E.g., analysis of Higgs constraints
Muehlleitner
Possible Future Higgs Measurements
Gianotti
What else is there?
Supersymmetry• Successful prediction for Higgs mass
– Should be < 130 GeV in simple models• Successful predictions for Higgs couplings
– Should be within few % of SM values• Could explain the dark matter• Naturalness, GUTs, string, … (???)
MSSM Higgs Masses & Couplings
Lightest Higgs mass up to ~ 130 GeVHeavy Higgs masses
quite close
ConsistentWith LHC
Muehlleitner
Is a lighter Higgsstill waiting?
CMSSM Search @ 8 TeV
p-value of simple models ~ 5% (also SM)
2012 20/fb
Scan of CMSSM
Buchmueller, JE et al: arXiv:1312.5250
Confronted with likelihood analysis of CMSSM
LHC Reach for Supersymmetry
51 20/fb2012
Squark mass
CMSSM
Favoured values of squark mass also significantlyabove pre-LHC, > 1.6 TeV
Buchmueller, JE et al: arXiv:1312.5250
Reach of LHC atHigh luminosity
If you Know of a Better Hole, go to it• The hierarchy problem is more
pressing than ever• SUSY is increasingly the best
solution we have• We have an evolving sense of
what SUSY models do not work• But SUSY is a framework, not a
model, and contains multitudes• This points us in new directions;
many novel possibilities for SUSY remain
Craig
Craig
Craig, Luty
• Future runs of the LHC:– Run 2: 30/fb @ 13/14 TeV– Run 3: 300/fb @ 14 TeV
• HL-LHC: 3000/fb @ 14 TeV?(proposed in CERN’s medium-term plan)
• HE-LHC: 3000/fb @ 33 TeV??(high-field magnets in the LHC tunnel)
• VHE-LHC: 3000/fb @ 100 TeV??(high-field magnets in 80/100 km tunnel)
Proton-Proton Colliders:Luminosity and Energy
Gianotti
Higgs Cross-Sections @ HE/VHE-LHC
VHE-LHC physicsStudies just starting
Gianotti
Reaches for Sparticles @ LHC, HE-LHC, VHE-LHC
VHE-LHC physicsStudies just starting
Gianotti
Where May CMSSM be Hiding?
Relic density constraint,assuming
neutralino LSP
JE, Olive & Zheng: arXiv:1404.5571
Stopcoannihilation
strip
Staucoannihilation
strip
Excluded byb s γ, Bs μ+μ-
Excluded by ATLASJest + MET search
Excluded because stau or stop LSP
LHC 300
HE-LHC
LHC 3000
• Extended by Sommerfeld effects on annihilations
• Compatible with LHC measurement of mh
• May extend to mχ = mstop ~ 6500 GeV
Exploring the Stop Coannihilation Strip
JE, Olive & Zheng: arXiv:1404.5571
Current limits(monojets), MET
LHC 300 (monojets), METHE-LHC (monojets), MET
LHC 3000 (monojets), MET100 TeV (monojets), MET
IntroductionStandard Model Particles:
Years from Proposal to DiscoveryLovers of SUSY:
be patient!